Lifting jack



L D. NILSON Sept. 27, 1932.

LIFTING JACK Filed April 20, 1931 3 Sheets-Sheet p 27, 1932- 1.5m. NILSON L8fl LIFTING JACK Filed April 20, 1931 3 Sheets-Sheet 2 @Wzzfoz Z r 3; 3325022,

M6,; omgya Patented Sept. 27, 1932 LEONARD D. NILSON, OF WAYZATA, MINNESOTA LIFTING JACK Application filed April 20,

in object of my presentinvention is to provide a lifting jack of'improved and simplified construction which is inexpensive to manufacture.

A further object is to provide a lifting jack having a novel arrangement of rack and pinion actuating mechanism for imparting lifting movement to the lifting head of the jack. 19 Another object is to provide a novel form of reversing mechanism for the holding and lifting pawls of the jaclr.

A further object is to so design a'j'ack that a high lift can be obtained with a rack bar of minimum length.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, :as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which: i

Figure 1 is a plan view of a curb service type of jack embodying my invention.

Figure 2 is a side elevation of the-same.

Figure 3 is a side elevation of a dolly type of jack embodying my invention.

Figure 4 is a sectional view on the line 44 of Figure 1 showing the mechanism of the jack.

Figure 5 is a transverse vertical sectional view on the line 55 of Figure 4.showing the relation of various parts of the jack.

Figures 6, 7,8 and9 are semi-diagrammatic figures illustrating different positions of the ratchet wheel, holding and lifting pawls and reversing mechanism of the jack, when being operated for lowering the lifting head.

Figure 10 is a semi-diagrammatic view showing the lifting arm, pinion and rack bar, lifting head, steady arm and rollerfor engaging the back of the rack 'bar so as to illustrate the operation thereof; and

Figure 11 is a similar view in less detail showing the parts when adjacent completely raised position.

On the accompanying drawings, I have used the reference numerals 10 to indicate 50 front wheels and the numerals 12 to indicate 1931., Serial No. 531,467.

rear wheels of the jackstructure, as shown in Figures 1, 2, 4 and 5. The structure shown 111 1 igure 3 will be described later. Front and rear axles l4 and 16 are provided for the wheels 10 and 12.

Side frames 18 are provided with suitable bosses 20 and 22 in which the axles l4 and 16 are positioned.- The side frames 18 areheld rigid with respect to each other by means of a stop bolt 24 and a shouldered pivot bolt 26. i v

A pair of lifting arms 28each has an upper end pivoted on thefbolt 26 and a lower end carrying a pin 30. Lifting head plates 32 are pivotedon the pin 30 and carry a lifting head pin 34. A lifting head 36 is pivoted on the pin 34 so that a high'zsurface 36a thereof may engage the .axle of an automobile, as shown in Figure 2, or the lifting head may beswung as indicated by the arrow 38 in Figure 4, so that an automobile a-Xle may engage with a low lug 36b thereof, or with an intermediate surface 32a formed on the lifting head plates 32;

For imparting lifting movement to the lift- .ing armr28, I provide a rack bar 40 having one end pivoted to the pin-3O and havingteeth meshing witha pinion 42. The pinion 42 is rotatable on-a shaft 44 and is integral with or connected with a pair of ratchet wheels 46.

A pair of steadying arms 48 have each an upper end pivoted on the shaft 44and a lower end pivoted on apin '50 carried by the lifting head plates 32. The pivot bolt 26, the shaft 44,,the pin 30 and the pin 50 form four corners of a parallelogram whereby when the lifting arm 28v is swung to a raised position, the lifting head '36 will remain level.

For retainin the rack bar 40 in proper mesh with the pinion 42,1 provide a roller 52 journalled on a pin '54.v The pin 54 is carried by the pair of steadying arms 48., whereby the roller 52 is swung about the shaft 44 as an axis during lifting movement of the lifting arms and since the rack bar 40 is connected with the lifting arm, it

also swings vabout the pinion, so that at all times .a line drawn between the axes 44 and 54 is approximately at right angles to the back of the rack bar40, thus insuring proper mesh between the rack bar and the pinion without binding.

The particular arrangement of the rack bar and the pinion with respect to the lifting arm, etc. is particularly desirable inasmuch as'by the construction shown, a maximum lift can be had with a rack bar of minimum length. This is because as the pinion 42 rotates, it imparts sliding movement to therackbar which acts as a thrust bar to swing the pin 30 about the axis 26, thus raising the lifting head. During the raising movement,- the rack bar also swings about the pinion so that in its raised position it has gained two or three teeth on the pinion, making it possible to get a predetermined travel of'the rack bar without so many teeth. Further- --more, the location of the axis 44 below the axis 26 and toward the axis 30 carries a distribution of forces throughout the parts of the jack in operation which produce the greatest leverage for operating the jack.

For instance,'it will be noted, as shown in Figure 10, that the lifting arm 28 or the line representing it, normally extends downwardly from the pivot 26, while the rack bar extends slightly upward from beneath the pinion 42. Rotation of' the pinion "causes the-rack bar to be thrust longitudinally, giving a raising movement to the lifting arm, which movement more nearly approaches'a vertical upward thrust as the lifting arm is raised as shown by dotted lines in this figure. In Figure 11, the'lifting arm is adjacent its highest position and it will be noted that there is a still more nearly vertical thrust being imparted to the rack'bar.

For rotating the pinion 42 and for retain ing itin any desired position, I provide lifting pawls 56 and holding pawls 59. The lifting pawls 56 are pivoted on a lifting pawl pin 58 carried by liftingpawlplates 60. The plates 60 are pivoted on the shaft 44 and are adapted to oscillate thereabout, carrying the lifting pawls 56 with'them.

The lifting pawls, of course, are made in pairs, the same as the ratchet wheels 46 with which they coact whereby to balance the strains throughout the parts and prevent binding of the jack, the lifting arms and steadying arms also being provided in pairs for this purpose. A spring 62 is'provided for normally retaining the lifting pawls 56 engaged with the teeth of the ratchet wheels 46. An actuating lever 64 is connected with the plates 60 for oscillating them, as will hereinafter be described.

The holding pawls 58 are'pivoted on the pivot bolt 26 and are suitably spaced from each other and from the lifting arms 28 by sleeves 66. They are n'ormallyretained in engagement with the teeth of the ratchet wheels 46 by a spring 68. A stop rod is provided for them to limit their outward movement during reversing operatlons.

The reversing mechanism of the jack consists of a reversing dog 72 pivoted on the lifting pawl pin 58 and connected by a spring I 74 with a reversing handle 76. The reversing handle 7 6 is located adjacent the handle portion 78 of the actuating lever 64. The reversing dog 72 has a reversing link 80 pivoted to a lug thereof, which lug may at timesengage a pin 82 of the lifting pawls 56. The reversing link 80 has a slot 84 type are swively mounted onthe cross frame 18?). Instead of the lifting head 36, the side plates 325 have a head 320 in which a spindle 860 is rotatably mounted.

The spindle 360'is formed on the lower end of a head 36d whereby the head is swivelly mounted.

The lifting pawl plates60a which carry the.

lifting pawl 56 are connected by a link 60?) with a notched sector lever'88. lever 88 is pivoted to a pin 90 carried by a bracket 92 extending forwardly from the cross member 186. An actuating lever 64a is pivoted to the pin 90 and carries a sliding dog 94 adapted to coact selectively with the notches of the sector 88. A control rod 96 is provided for the dog94 which has ahead 98 adjacent the handle 78a. The dog 94 is preferably retained in any of the notches of the sector 88 by spring means.

Practical operation In the operation of my device, reciprocating motion lmparted to the actuatmg lever 64 causes reciprocation of the plates 60 and the lifting pawls 56- about the axis 44. This successively causesthe ratchet wheels 46 to be rotated step by step, the holding pawls 58 preventing reverse rotation thereof in the ordinary manner.

In reversing the operation of a jack for lowering a load, the reversing handle 76 is drawn towardthe operating handle 78 which causes tension on the spring 74 to be suflicient to overcome both the tension of the spring 62 and of the spring 68. Referring to Figure 6, with the actuating lever moving upwardly,

the tension of the spring 74, because of the Itwill be" noted that the spring 68 of the holding pawl 58 is retained against the ratchet wheel.

Further upward movement of the actuating lever causes a tooth of the ratchet wheel to engagethe holding pawl 58 so that the load The sector is then carried thereby. Still further movement upward of the actuating lever will free the lifting pawl so that the spring 74 will disengage the same, as shown in Figure 7.,

The actuating lever is then moved downwardly as shown in Figure 8 which first causes coaction between the pin 86 and the upper end of the slot 84 so that the tension of the spring 74: is relieved from the pin 82, thus allowing the lifting pawl to re-engage the ratchet wheel. Further downward movement of the actuating lever as shown in Figure 9 will rotate the ratchet wheel for imparting slight lifting movement to the lifting head sufficient to allow the tension of the spring 74: to overcome that of the spring 68 through the reversing link connection 80, so as to release the holding pawl from the ratchet wheel. The cycle of operations in lowering the jack is then repeated, beginning with Figure 6. r 1

From the foregoing description, it will be obvious that I have provided a particularly eificient actuating-mechanism for a jack in designing a pinion and rack bar for coaction with each other and for operation in the specific manner set forth. I have also provided an effective and simple means for retaining the rack and pinion in proper mesh with each other throughout the lifting and lowering movements of the jack.

The frame of the jack can be considerably altered as for instance by providing either the type shown in Figure 2 or the type shown in Figure 3 and other changes may also be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. In a lifting jack, a frame, alifting arm having one end pivoted thereto, a pinion journalled on said frame at a point spaced from the pivotal connection of the lifting arm thereto, a rack bar having one end-pivoted to the other end of the lifting arm and meshing with said pinion, means for rotating said pinion and a lifting head carried by said other end of said lifting arm.

2. In a lifting jack, 2. frame, a lifting arm having one end pivoted thereto, a pinion iournalled on said frame at a point spaced from the pivotal connection of the lifting arm thereto, a rack bar having one end pivoted to the other end of the lifting arm and meshing with saidpinion, ratchet and pawl means for rotating said pinion and a lifting head carried by said other end of said lifting arm.

3. In a lifting jack, a frame a lifting arm having one end pivoted thereto, a pinion journalled on said frame at a point spaced from the pivotal connection of the lifting arm thereto, a rack bar having one end pivoted to the other end .of the lifting arm and meshing with said pinion, means for rotatingsaid pinion, a lifting head carriedaby said other end of said lifting arm, a steadying link having one end pivoted to the frame and its other end pivoted to the lifting head for maintaining the same in level position and a roller carried by said steadying link and engaging said'rack bar to retain the same in mesh with said pinion.

5. In a lifting jack, a frame, a lifting arm having one endpivOt'ed thereto, a. pinion journalled on said frame at a point spaced from the pivotal connection of the lifting'arm thereto, a rack bar having one end pivoted-to the other end of the lifting arm and meshing V with said 'plnion, means for rotating said pinion, a lifting head carried by said other end of said lifting arm, a steadying link pivoted to said frame on the axis of said pinion and means carried-thereby to engage said rack bar and cause the same to mesh with said pinion throughout the lifting movement of the lifting ar 6. In a lifting jack, a triangular wheeled frame, a lifting arm having one end pivoted thereto adjacent an upper corner thereof, a lifting head pivoted to the other end of said lifting armand normally positioned adjacent a lower corner of said triangular frame, a shaft journalled in said frame below said upper corner andtoward said lower corner thereof, a thrust bar movable relative to said shaft and having one end pivoted to the lifting head end of said lifting arm and'means for imparting'movement to said thrust bar.

7. In a lifting jack, a triangular wheeled frame, a lifting arm having one end pivoted thereto adjacent anupper corner thereof, a

liftinghead pivoted to the other end of said lifting arm and normally positioned adjacent a lower corner of said triangular frame, a shaft journalled in said frame below said upper corner and toward said lower corner thereof, a thrust bar movable relativeto said shaft and having one end pivoted to the lifting head end of said lifting arm and ratchet and pawl means for said thrust bar relative to said shaft.

8. In a lifting jack, a triangular wheeled frame, a lifting arm having one endpivoted shaft journalled in said frame below said -lifting headpivoted to the other end of'said thereto adjacent an upper corner thereof, a a

lifting arm and normally positioned adj acenta lower corner of said triangular frame, a

upper corner and toward said lower corner thereof, a-thrust bar movable relative to said shaft and having one end pivoted to the lifting head end of said lifting arm, a steady link having one end pivoted on said shaft and its other end pivoted to said lifting head and means for imparting movement to said thrust bar. I r

9. Ina liftingjack, a wheeled frame, a lifting arm having one end pivoted thereto, a

liftinghead pivoted to the other end of said lifting arm, a shaft ournalled in said frame, a thrust bar movable relatlve to said shaft and having one end pivoted to the liftmg i head end of said lifting arm and ratchet and pawl means for moving tive to said shaft a 10. In a lifting jack, an elongated wheeled frame, a lifting arm having one end pivoted thereto, spaced from one end of said frame and normallyextending forward and downsaid thrust bar relaward from the pivot point, apinion rotatdog and having a pin and slot connection 'ably carriedby said frame on anaxis below said pivot point and toward the other end of the lifting arm, a rack barmeshing with the lower side of said pinion and having one end operatively connected with saidother end of said lifting arm and means for imparting 'rotationto sald pinion, said means comprising a ratchet wheel with which said pinion is rotatable, a lifting pawl coacting with said 7 ratchet wheel, an actuating lever at the other end of said elongated frame and a link operatively connecting said lever with said lifting pawl, said actuating lever'comprising a pair of members, one of which is adjustable relative to the other for changing the arc of arm and means for imparting rotation to said pinion including a ratchet wheel, lifting and holding pawls for coaction therewith, spring means for constraining said pawls toward engagement with said ratchet wheel, a reversing dog, resilient means constraining the same to swingsaid lifting pawl against the actlon of the sprlng means thereon and a reversing link extending from sa1d reversing with said holdingpawl v 12'. Ina lifting jack, a wheeled frame, a lifting arm having one end pivoted thereto and normally extending forward and downward from the pivot point, a pinion rotatably carried by said frame, a rack bar meshing therewith and having one end operatively connected with the lifting end of said lifting arm, 'a lifting head carried by said lifting arm and a steadying link having one end pivoted to said frame on the axis of said pinion and itsother end pivoted to said lifting head.

arm, a lifting head carried by said lifting arm, a steadying link having one end pivoted to said frame on the axis of said pinion and its other end pivoted to said lifting head and means carried by said steadying link and engagingsaid rack bar to retain the same in mesh with said pinion.

14. In a lifting jack, a wheeled frame, a lifting arm having one end pivoted thereto and normally extending forward and downward from the pivot point, a pinion rotat-" ably carried by said frame, a rack bar meshing therewith and having one end operatively connected with the lifting end of said lifting arm, a lifting head carried by said lifting arm, a steadying linkhaving one end pivoted to said frame on the axis of said pinion and its other end pivoted to said lifting head and a roller carried by said steadying link and engaging the back of said rack bar to retain it engaged with said pinion.

15. In a lifting jack, a wheeled frame, a

lifting'arm having one end pivoted thereto,

the other end of said lifting arm constituting a lifting end and normally located spaced forward and downward from the pivot end thereof, a pinion rotatable about an axis below said pivot end and toward said lifting end, a rack bar meshing therewith and having one end pivoted to said lifting end andmeans pivoted on said axis and thereby ioo its

swingable thereabout and engaging said rack 7 bar to retain the same in mesh with said pinion.

16. In a lifting jack, a wheeled frame, a lifting arm having one end pivoted thereto, the other end of said lifting arm constituting a lifting end and normally located spaced forward and downward from the pivot end thereof, a pinion rotatable about an axis below said pivot end and toward said lifting end, a rack bar meshing therewith and having one end pivoted to said lifting end and means pivoted on said aXis and thereby swingable thereabout and engaging said rack bar to retain the same in mesh with said pinion, said means being operatively connected with the lifting end of said lifting arm whereby such swinging movement is imparted thereto by the lifting arm as it is swung on its pivot.

17. In a lifting jack, a Wheeled frame, a

lifting arm having one end pivoted thereto,

the other end of said lifting arm constituting a lifting end and normally located spaced forward and downward from the pivot end thereof, a pinion rotatable about an axis be' low said pivot end and toward said lifting end, a rack bar meshing therewith and havq ing one end pivoted to said lifting end and means pivoted on said axis and thereby swingable thereabout and engaging said rack bar to retain the same in mesh with said pinion, said means being operatively connected with the lifting end of said lifting arm whereby such swinging movementis imparted thereto by the lifting arm as it is swung on its pivot and a lifting head pivoted to said lifting end of said lifting arm, said operative connection being associated with said lifting head for retaining the same in level position.

18. In a lifting ack, a frame, a lifting arm having one end pivoted thereto, a lifting head on the other end of said lifting arm and normally positioned adjacent the lower edge of said frame, a shaft journalled in said frame at a point spaced from the pivotal connection of said lifting arm to said frame, a rigid thrust bar movable relative to said shaft and having one end pivoted to the lifting head end of said lifting arm and means for imparting movement to said thrust bar.

19. In a lifting jack, a frame, a lifting arm having one end pivoted thereto, a lifting head on the other end of said lifting arm and normally positioned adjacent the lower edge of said frame, a shaft journalled in said frame at a point spaced from the pivotal connection of said lifting arm to said frame, a rigid thrust bar movable relative to said shaft and having one end pivoted to the lifting head end of said lifting arm and means mounted on said shaft for imparting movement to said thrust bar, said means being rotatable about said shaft during such sliding movement.

20. In a lifting jack, a frame, a lifting arm having one end pivoted thereto, a lifting head on the other end of said lifting arm and nor mally positioned adjacent the lower edge of said frame, a shaft journalled in said frame at a point spaced from the pivotal connection of said lifting arm to said frame, a rigid thrust bar movable relative to said shaft and having one end pivoted to the lifting head end of said lifting arm, means mounted on said shaft for imparting movement to said thrust bar and a member pivoted to said shaft and guiding said thrust bar for retaining the thrust bar in equally spaced relation to said shaft throughout such movement of the thrust bar.

LEONARD D. NILSON. 

